1.0 

 .8 



.6 



M 



O _ 



"S .2 



60 

 O 



o .1 



"o 



a 



* .08 



1.06 



E 



W 



1.04 



.02 



12 3 4 



Concentration or depth 



Fig. IV-11. Relation between spectral transmission-factor and depth or concen- 

 tration of a solution of methyl green. (From data by M. Luckiesh [1917].) 



6 C, 3 



Fig. IV-12. Optical system of a colorimeter or nethelometer for monochromatic 

 light. (By courtesy of Kipp and Zonen.) 



150 



